Mount structure for electric lamps



Feb. 14, 1950 J. E. sToNi: ETAL 2,497,566

MOUNT STRUCTURE FOR ELECTRIC LAMPS Filed April 27, 1949 Inverfirws:Joseph E. S-lrone, John O. GeissbuhLeT". b5 62 Their A trtorheg.

Patented Feb. 14, 1950 2,497,566 MOUNT STRUCTURE FOR ELECTRIC LAMPSJoseph E. Stone, Cleveland Heights, and John 0. Geissbuhler, SouthEuclid, Ohio, assignors to General Electric Company, a corporation ofNew York Application April 27, 1949, Serial No. 90,012

3 Claims.

This invention relates to electric incandescent lamps in general, andmore particularly to a mount construction therefor.

There are many so-called rough service applications where an electricincandescent lamp is subjected to considerable vibrations, jars orimpacts, for instance in locomotive headlights, automatic miningmachinery, earth moving equipment, tractors and other like equipment. Insuch cases, it is highly important that the filament or light source ofthe lamp be so supported that the forces developed by the vibrations orshocks be sumciently dissipated in order to prevent distortion of thehot filament such as is apt to-result in premature breakage or failureof the filament with consequent short lamp life.

It is an object of our invention therefore to provide an electricincandescent lamp having it filament so supported as to avoiddetrimental effects of lamp vibration or impacts.

Another object of our invention is to provide an electric incandescentlamp having a flexible mount structure of simple form and which willeffectively withstand vibration and impacts to whichthe lamp may besubjected in service.

Further objects and advantages of our inven tion will appear from thefollowing description of a species thereof, and from the accompanyingdrawing. v

In the drawing, Fig.1 is a sectional view of an electric incandescentlamp according to the invention, and Fig. 2 is an enlarged perspectiveview of the mount structure thereof} Inaccordance with the invention,the filamentsupporting end or section of'an electric incandescent lampmount is rendered flexible in all directions by making the lead-in wiresor inleads of springy material and' forming them, inwardly of the lampenvelope, with laterally extending and approximately opposed arcuateintermediate portions, of more or less semicircular shape, which act asa cushion between the upper filament-supporting end of the mount and thelower anchored end of the mount to absorb any shocks or vibrations towhich the lamp may be subjected in service. 1 7

Referring to the drawing, the invention is there shown as applied to anelectric incandescent lamp of the sealed beam type. disclosed in U. S.Patent 2,148,314, D. K. Wright. and comprising a sealed glass envelopeor bulb l consisting of preformed pressed glass reflector and coverglass sections {2 and 3, respectively, sealed together at theirperipheries by fusion, as indicated at 4. The inner surface 5 of thereflector section 2 is formed either of paraboloidal shape as shown, orof any other desired optical shape, and is provided with a reflectingcoating 6 of aluminum, silver or other similar light-reflectivematerial.

Cal

Mounted on the rear outer side of the reflector section 2 at the regionof the apex or center thereof is a base structure 1 of the general typeshown and described in U. 8. Patent 2,272,- 512, Cotman, and comprisinga pair of terminal contacts 8-8 in the form of metal straps or lugswhich are suitably fastened, as by solder ing for instance, to theclosed nippled ends 9 of respective metal ferrules or thimbles Itll. Thecontact lugs 8-8 are provided with screw terminals "-41 for connectingcurrent supply wires thereto. The ferrules ill-I0 are formed of asuitable metal which will readily wet and adhere to the glass of thereflector section 2 and they are provided with skirt portions I! whichare feathered to knife edges embedded and fused in the glass of thereflector section 2 around respective openings or passageways l1 throughthe wall thereof. The envelope l is provided with an exhaust tubulationl4 communlcating with the interior of the envelope through an exhaustopening I5 in the envelope wall at the apex of the reflector section 2.After exhaustion of the envelope through the tubulation it and. ifdesired, introduction of a suitable gas filling such as nitrogen orargon, the tubulation H is sealed or tipped-oil as indicated at I6.

Mounted within the envelope l and supported solely from the metalferrules Ill-40 in spaced relation to'the envelopewalls is a lamp mountstructure 11 according to the invention and comprising a pair of wireinleads l8--l8 secured and anchored at their outermost ends within thenipples 9 of the ferrules, as by solder l9 as shown. The inleads I8 aremade of any suitable spring material, such as molybdenum or hard nickelfor instance, which will not-lose its temper or springy character whenheated to high temperatures such as are encountered during the operationof the lamp. From the ferrules l0l0,'the inleads l8l8. extend in more orless parallel spaced relation through the openings I3-I3 in the wall ofthe reflector section 2 and into the envelope l where they areconnected, at their innermost ends, to opposite ends of a filament 20preferably formed of tungsten wire. In the specific case illustrated,the filament 20 is composed of two convergent coiled sections orsegments joined by a bight or loop portion 2| to form a V-shapedfilament approximately lying in the plane of-the parallel extendingportions of the inleads and mounted in the envelope l symmetricallyabout the optical axis of the reflecting surface 6 and approximatelycentered atthe focus thereof, with the apex of the V pointing forwardlyas shown and with the plane of the filament lying approximately in thereflector axis. The connection of the filament ends to the inleads l8-I8may be through small metal connecting lugs 22 suitably fastened to theinner ends of the inleads, as by welding, and provided with U-clamps 23within which the free ends of the filament are clamped as shown in Fig.2. The filament 20 is additionally supported at the bight 2| thereof byan anchor or support wire 24 provided at one end with a hook 25 withinwhich the filament bight 2| is hooked. The other end of the support wire24 is suitabl fastened in place on an insulated part of the mountstructure in a manner to be hereinafter described.

In accordance with the invention the inleads l8-l8, inwardly of theenvelope I, are formed with laterally bent approximately opposed arcuateor curved intermediate portions 28-28 which lie approximately in acommon plane transverse to the generally parallel extending outer andinner co-planar portions 21 and 28, respectively, of the inleads I 8-l8.As shown in Fig. 2, the arcuate portions 26 of the inleads areapproximately in the shape of opposed semi-circles located on oppositesides of the common plane of the inleads and opening or facing towardeach other and having a diameter somewhat less than the spacing of theouter portions 21-21 of the inleads, with the diametral chords of thesemicircles (i. e., the imaginary lines joining the opposite ends of thesemi-circles) lying approximately in the common plane of the outer andinner parallel portions 21 and 28 of the inleads. These arcuateintermediate portions 28-28 of the inleads, being free of or spaced fromthe walls of the envelope and being made 01' a springy material,vtherefore impart flexibility in substantially all directions (i. e., 360solid angle) to the filament-supporting end 01' the mount I'I wherebyany vibrations or shocks to which the lamp may be subjected in serviceare effectively absorbed or cushioned by such yielding intermediateportions. 28. I

To maintain the points of support of the filament in fixed relation toeach other at all times independent of any unitary movement thereof dueto lamp vibration or shock, the inner portions 28-28 of the inleadsi8-l8 are rigidly tied togather and held in parallel relation bysuitable insulative tie means which, in the particular case shown,comprises a pair of spaced cross-bars or bridges 29 and 30 eachconsisting of a short length of glass rod 3| having support wires 32wall and connected at their inner ends to said embedded in andprojecting from its opposite ends. The cross-bars 28, 30 are secured tothe inner portions 28-28 of the inleads, at spaced points therealong, bysuitably fastening the support wires 32 thereto, as by welding forinstance. The intermediate support wire 24 for the filament 28 isembedded and anchored in the glass rod 3| of the innermost cross-bar 29,thus maintaining the intermediate support point for the filament infixed relation to the end supports thereof at all times. The mountstructure I! according to the invention therefore includes as a partthereof a filament-supporting section or unit, comprising the innerportions 28-28 of ,the inleads, the

cross-bars 29, 38 and the intermediate support wire 24, which holds thefilament 28 in proper relation at all times and which is capable ofmoving as a unit, withoutrelative movement between the filament and theadjacent supporting parts of the said unit, during vibration or othersudden movement of the lamp.

From the foregoing it will be evident that the mount structure l1comprising .our invention provides a simple and effective flexiblesupporting arrangement for the filament whereby any vibrations, jars orimpacts to which the lamp may be subjected in service are readilyabsorbed by the yielding arcuate intermediate portions 28-28 of theinleads which act as an elastic connection or cushion between the inneror filament-supporting section of the mount and the outer or anchoredsection of the mount to efiectively minimize distortion of the hotfilament by such lamp vibrations or shocks, thus rendering the entirelamp structure especially useful for rough service applications such asa locomotive headlight or as a lighting unit for automatic mining orearth moving equipment, tractors and other similar equipment where thelamp is ordinarily subiected to unusual shock or vibration.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. An electric incandescent lamp comprising an envelope, a filament in'said envelope. inleads anchored to and supported from the wall of said.envelope and extending into the envelope from .rigidly tying the innerend portions of the inleads together, said inleads being providedintermediate their anchored ends and their said bridge means withlaterally extending curved portions each approximately located in aplane transverse to the inleads and spaced from the envelope wall toimpart flexibility to the said inleads.

, 2. An electric incandescent lamp comprising an envelope, a filament insaid envelope, inleads anchored to and supported from thewall of saidenvelope and extending into the envelope from their wall anchorages inthe same. general direction and in spaced relation to the envelopefilament, and bridge means 'insulatively and rigidly tying the inner endportions of the inleads together, said inleads being providedintermediate their anchored ends and their said bridge means withlaterally extending approximately opposed arcuate portions eachapproximately located in a plane transverse to the inleads and spacedfrom the envelope wall to impart flexibility to the said inleads.

- 3. An electric incandescent lamp comprising an envelope, a filament insaid envelope, inleads anchored to and supported from the wall of saidenvelope and extending into the envelope from their wall anchorages inthe same general direction and in spaced relation to the envelope walland connected at their inner ends to said filament, and bridge meansinsulatively and rigidly tying the inner end-portions of the inleadstogether, said inleads being provided intermediate their anchored endsand their said bridge means with laterally extending opposed arcuateportions of approximately semicircular shape approximately located in acommon plane transverse to the inleads and spaced from the envelope wallto impart flexibility to the said inleads.

, JOSEPH E. STONE.

- JOHN. O. GEISSBUHLER.

No references cited.

